package org.apache.lucene.analysis;

/**
 * Licensed to the Apache Software Foundation (ASF) under one or more
 * contributor license agreements.  See the NOTICE file distributed with
 * this work for additional information regarding copyright ownership.
 * The ASF licenses this file to You under the Apache License, Version 2.0
 * (the "License"); you may not use this file except in compliance with
 * the License.  You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

import java.io.IOException;

/**
 * A TokenFilter is a TokenStream whose input is another token stream.
 * <p>
 * This is an abstract class. NOTE: subclasses must override at least one of
 * {@link #next()} or {@link #next(Token)}.
 */
public abstract class TokenFilter extends TokenStream {
	/** The source of tokens for this filter. */
	protected TokenStream input;

	/** Construct a token stream filtering the given input. */
	protected TokenFilter(TokenStream input) {
		this.input = input;
	}

	/** Close the input TokenStream. */
	public void close() throws IOException {
		input.close();
	}

}
